It’s 2014. A hundred years ago, the assassination in Sarajevo of Archduke Franz Ferdinand initiated a series of calamitous events that brought on World War I. And the way WWI ended (with the Versailles Treaty) led to yet another series of events that brought Hitler to power in Germany–and this led to WWII.

So, basically, the first half of the 20th century was a mess.

Are we smart enough now, a century on, not to repeat the mistakes of the first half of the last century? As reported in The Independent recently, Margaret MacMillan, a historian at Cambridge, isn’t so sure:

“It is tempting – and sobering –to compare today’s relationship between China and the US with that between Germany and England a century ago,” Professor MacMillan writes. She points to the growing disquiet in the US over Chinese investment in America while “the Chinese complain that the US treats them as a second-rate power”.

Another similarity highlighted by the historian is the belief that a full-scale war between the major powers is unthinkable after such a prolonged period of peace. “Now, as then, the march of globalisation has lulled us into a false sense of safety,” she says. “The 100th anniversary of 1914 should make us reflect anew on our vulnerability to human error, sudden catastrophes, and sheer accident.

“Instead of muddling along from one crisis to another, now is the time to think again about those dreadful lessons of a century ago in the hope that our leaders, with our encouragement, will think about how they can work together to build a stable international order.”

Wise counsel, but why don’t I feel frightened? It feels like today’s national governments and international bodies really do have it covered; they’ve learned key lessons from the 20th century, and are determined not to repeat them.

And we have nuclear weapons now. They focus the mind, and force caution all around. People don’t tend to drive fast when navigating narrow mountain roads.

But maybe my complacence is folly. I do worry about Pakistan and India. And Iran and Israel. And the Koreas. Any one of these could make for a hell of a mess, bringing on a world war and maybe even crashing civilization altogether. (For example, a nuclear winter from an exchange of a hundred nuclear weapons between Pakistan and India is not out of the question.)

But I don’t see any of this as likely. And I don’t see China and the US ever coming to serious blows. My sense is that the temperature between nations is coming down the further we enter the 21st century. It’s very different from a hundred years ago.

And most people simply want to make money and cut trade deals. They’ve got their religious and national allegiances, but know the tragedy of war. And most contemporary world leaders know the idiocies of absolutist religion and nationalism, and are careful not to over-stoke these. The grotesque foreign policy of the Bush years, for example, still lingers in the minds of a lot of global leaders.

And urbanization gives me hope. People living in Shanghai and people living in New York have a lot in common. Improved communication also gives me hope. Science, technology, economic growth, and increasing energy efficiency gives me hope.

And Obama gives me hope. I’m relieved that the US is unlikely to be led by a warmonger any time soon. The liberal trend in the American electorate probably gives us a good twenty years or more of relatively calm presidents at the wheel. There’s a reason stock markets are up. People with money think trade, not war, is our future. I think they’re right.

So we need Casandras like Margaret MacMillan; they keep us sober. And she’s right that now is the time for a renewed commitment to building “a stable international order.” (Of course, it’s always the right time for this; the work of peace is never wholly accomplished.) But we need to hear from Pollyanna as well. And so I guess I’m playing that role now, and will say it outright: The global human future is more likely to be bright rather than dim. Steady as she goes. Keep calm and carry on.